Multiple choice

An electric bulb has a filament made of

  1. Copper

  2. Iron

  3. Lead

  4. Tungsten

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Tungsten is used in electric bulb filaments because it has an extremely high melting point (~3422°C) and low vapor pressure at high temperatures. Copper, iron, and lead would melt or evaporate quickly at the temperatures required for light emission.